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#![allow(clippy::useless_vec, clippy::manual_repeat_n)]
use std::iter::repeat;
fn main() {
resize_vector();
extend_vector();
mixed_extend_resize_vector();
from_empty_vec();
}
fn extend_vector() {
// Extend with constant expression
let len = 300;
let mut vec1 = vec![0; len];
// Extend with len expression
let mut vec2 = vec![0; len - 10];
// Extend with mismatching expression should not be warned
let mut vec3 = Vec::with_capacity(24322);
vec3.extend(repeat(0).take(2));
let mut vec4 = vec![0; len];
}
fn mixed_extend_resize_vector() {
// Mismatching len
let mut mismatching_len = Vec::with_capacity(30);
mismatching_len.extend(repeat(0).take(40));
// Slow initialization
let mut resized_vec = vec![0; 30];
let mut extend_vec = vec![0; 30];
}
fn resize_vector() {
// Resize with constant expression
let len = 300;
let mut vec1 = vec![0; len];
// Resize mismatch len
let mut vec2 = Vec::with_capacity(200);
vec2.resize(10, 0);
// Resize with len expression
let mut vec3 = vec![0; len - 10];
let mut vec4 = vec![0; len];
// Reinitialization should be warned
vec1 = vec![0; 10];
}
fn from_empty_vec() {
// Resize with constant expression
let len = 300;
let mut vec1 = vec![0; len];
// Resize with len expression
let mut vec3 = vec![0; len - 10];
// Reinitialization should be warned
vec1 = vec![0; 10];
vec1 = vec![0; 10];
macro_rules! x {
() => {
vec![]
};
}
// `vec![]` comes from another macro, don't warn
vec1 = x!();
vec1.resize(10, 0);
}
fn do_stuff(vec: &mut [u8]) {}
fn extend_vector_with_manipulations_between() {
let len = 300;
let mut vec1: Vec<u8> = Vec::with_capacity(len);
do_stuff(&mut vec1);
vec1.extend(repeat(0).take(len));
}
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